一. vue对象的生命周期
1). 初始化显示
* beforeCreate()
* created()
* beforeMount()
* mounted()
 beforeCreate() {
            console.log('beforeCreate()')
        },

        created() {
            console.log('created()')
        },

        beforeMount() {
            console.log('beforeMount()')
        },

        mounted () {
            console.log('mounted()')
            // 执行异步任务
            this.intervalId = setInterval(() => {
                console.log('-----')
                this.isShow = !this.isShow
            }, 1000)
        },

  


2). 更新状态
* beforeUpdate()
* updated()
 beforeUpdate() {
            console.log('beforeUpdate()')
        },
        updated () {
            console.log('updated()')
        },

  


3). 销毁vue实例: vm.$destory()
* beforeDestory()
* destoryed()
beforeDestroy() {
            console.log('beforeDestroy()')
            // 执行收尾的工作
            clearInterval(this.intervalId)
        },

        destroyed() {
            console.log('destroyed()')
        },

        methods: {
            destroyVue () {
                this.$destroy()
            }
        }

  


二. 常用的生命周期方法
created()/mounted(): 发送ajax请求, 启动定时器等异步任务
beforeDestory(): 做收尾工作, 如: 清除定时器